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Calculate Safety Stock to Prevent Overselling in Singapore

Here’s a quick look at the main formulas we’ll be covering. Think of this as your cheat sheet for later.

Key Safety Stock Formulas At a Glance

Formula TypeBest ForKey Inputs Required
Basic Rule-of-ThumbSellers who are new to safety stock or have relatively stable sales and reliable suppliers. A great starting point.Max/Average Daily Sales, Max/Average Supplier Lead Time
Demand Variance (Z-Score)Businesses with unpredictable customer demand but consistent supplier lead times. Perfect for trending products.Standard Deviation of Sales, Average Lead Time, Desired Service Level (Z-score)
Lead Time VariabilitySellers who face unreliable supplier delivery times but have steady customer demand. Essential for managing import delays.Average Daily Sales, Standard Deviation of Lead Time, Desired Service Level (Z-score)
Periodic Review AdjustmentsAnyone not using a perpetual inventory system; those who review and order stock at fixed intervals (e.g., weekly).All of the above, plus the time between your inventory reviews.

Each of these methods solves a slightly different problem, from basic protection to fine-tuning for specific supply chain headaches. We’ll walk through exactly how to use them.

Unlocking Your Inventory Turnover Days

Inventory turnover days is a metric that tells you, on average, how many days it takes for your business to sell its entire stock.

Think of it like the fresh ingredients in a restaurant’s kitchen. Inventory turnover days shows how quickly you use up all those ingredients to serve dishes before needing to restock.

Perpetual inventory system: Real-Time Stock Control for Your Business

Imagine trying to run your business without knowing how much money is in your bank account. You wouldn’t, right? A perpetual inventory system brings that same real-time clarity to your products. It’s a live, constantly updated view of your stock, recording every sale, return, and new delivery the moment it happens.